1. Technical Field
Embodiments of the invention relate generally to hull conversion of an existing vessel such as an oil tanker vessel or a bulk carrier for integrating one or more tanks for storing hydrocarbon and non-hydrocarbon fluids.
2. Description of Related Art
Substantial cost savings can be realized by modifying or converting hull designs of vessels to extend the life of the vessels rather than constructing a new vessel.
U.S. Pat. No. 7,077,071 B2 (Neu) discloses a method for converting a single-hull vessel to a double hull vessel, and the converted double hull vessel. The single hull vessel to be converted has an outer hull surrounding a center cargo tank flanked by a port wing tank and a starboard wing tank, with spaced-apart transverse bulkheads extending between the port and starboard wing tanks to form one or more central tanks. An elevated floor is added to the central cargo tanks by installing new bottom plating spanning the transverse bulkheads and the sidewalls of the wing tanks. Support members are added to increase the strength of the elevated floor, the cargo tank, and the wing tanks, as needed. A sealed compartment is formed by the new elevated floor, the outer hull, and the sidewalls and bulkheads to protect the cargo from leaking out of the vessel should the integrity of the single hull be breached. The method achieves conversion of the single hull vessel to a double hull construction without breaching the integrity of the pre-existing single outer hull, and thus is faster and easier in converting single hull vessels to minimize cost of conversion and vessel outage.
U.S. Pat. No. 6,708,636 B1 (Hagner) discloses a rebuilt double hull tanker and a method of rebuilding an existing single hull tanker into a rebuilt double hull tanker. The rebuilt double hull tanker includes a rebuilt double hull comprising a new double bottom hull and new double side hulls. The internally rebuilt double bottom hull includes the existing outer bottom hull and a new inner bottom hull that is disposed internal and spaced apart from the existing outer bottom hull. The externally rebuilt double side hulls (e.g., port and starboard) include the existing inner side hulls and new outer side hulls disposed external and spaced apart from the existing inner side hull. The rebuilt double bottom hull is connected at each end (e.g., at the turn of the bilge) to the rebuilt double side hulls. The method includes forming the new double hull, including a new double bottom hull and new double side hulls, over at least the cargo carrying portion of the tanker by installing the new inner bottom hull internally over the existing outer bottom hull through access holes cut into the sides of the tanker and installing the new double side hulls externally over the existing inner side hulls.
Additional information relating to hull conversion or rebuild can be found in U.S. Pat. No. 5,909,715 (Menon), International Application Publication No. WO 2007/089159 (Framo Engineering AS), U.S. Pat. No. 5,189,975 (Zednik et al.), and U.S. Pat. No. 6,170,420 (Hagner et al.).